Wirelessly posted (htc Pocket PC: Mozilla/4.0 (compatible; MSIE 6.0; Windows CE; IEMobile 8.12; MSIEMobile6.0) Sprint T7380)
The key switch is most likely attached to a printed circuit board which would probably mean you would have to replace the entire board so it is probably fixable. The thing is, unless you buy all the parts you need and you are able to open it up and replace those parts and put it back together without messing something else up then it may be a lost cause.
Good Luck to you! Let us know your results if you go for it.